Answer:
a. Environmental factors determine all genetic traits
Step-by-step explanation:
The environmental factors are the basis for the evolution of the organisms. The environment is where the organisms live, so in order for them to be able to survive, they need to evolve traits in accordance to the environment, traits that would be advantageous for their survival. This leads to changes in the genes of the organisms, changes where the genes that contribute to easier survival remain, new advantageous ones develop, while the ones that are a limiting factor are slowly removed from the gene pool. This of course takes longer period of time and it happens gradually.